Rice University Biodiesel Initiative (RUBI) is to blame if the exhaust from a Rice lawn mower brings on a sudden craving for french fries.

Founded a year ago by a handful of graduate and undergraduate students, RUBI is working to turn all of the waste cooking oil from Rice kitchens into clean-burning fuel for campus vehicles. This explains why the lawn mower smells sweet instead of sooty; biodiesel’s made from food.

Photo by Jeff Fitlow

Rice University Biodiesel Initiative (RUBI) turns waste cooking oil from Rice’s kitchens into clean-burning fuel for lawn mowers on campus. So far RUBI produces only a few gallons of biodiesel each month, but the group hopes to ramp up production this fall to several thousand gallons per year.

“I’m lucky I haven’t gained any weight yet,” said Roy Perez, an equipment operator in Facilities, Engineering and Planning who has been using RUBI-supplied biodiesel in his riding mower for several months.

So far, RUBI is supplying enough biodiesel to run Perez’s mower for only about one week each month, but the group hopes to ramp up production this fall to several thousand gallons per year. That would be enough biodiesel to power all of Rice’s large mowers and a new diesel-powered van for Rice Catering.

“We’ve gotten a lot of encouragement from the departments of housing and dining, grounds maintenance and transportation — all of the people that might have a use for this fuel someday,” Rice Sustainability Planner Richard Johnson said. “Housing and dining is particularly intrigued by the idea that they can use their waste cooking oil to power a catering van.”

In chemical terminology, biodiesel is a blend of methyl esters. It is made by using methanol and a catalyst to break down the triglycerides in vegetable oil into methyl esters and glycerin. The process makes the oil less viscous and fools diesel fuel injectors into thinking they are still pumping petroleum diesel.

In fact, biodiesel was the original fuel used to power the first compression engine invented by Rudolph Diesel, as well as some of Henry Ford’s early diesel engines, said Pedro Alvarez, the George R. Brown Chair of Civil and Environmental Engineering. Alvarez said the U.S. abandoned biodiesel in favor of petroleum diesel early in the 20th century, but the nation stands to benefit by using more biodiesel in the future.

“The development of biodiesel in the U.S. is a stepping stone to gaining more strategic independence from imported oil,” Alvarez said. “It will also stimulate rural economies, which is important for maintaining food security.”

Rice’s biodiesel program also could have long-term payoffs in terms of research at Rice, said Kyriacos Zygourakis, the A.J. Hartsook Professor in Chemical Engineering, professor in bioengineering and RUBI faculty adviser. Zygourakis said biodiesel is a cleaner-burning fuel than petroleum diesel in all respects save one: biodiesel produces more nitrogen oxides. Known as “NOx,” nitrogen oxides are air pollutants in automobile exhaust that are major contributors to ozone pollution in Houston and other cities.

“There isn’t much data out there about the amount of NOx that’s produced when you burn biodiesel in real-world conditions,” Zygourakis said. “Making and using this fuel at Rice gives Rice a potential test bed for both quantifying this problem and testing additives and other technologies that could reduce NOx emissions and open the door for wider use of this largely clean-burning fuel.”

RUBI co-founder Matt Yarrison, a graduate student in chemical and biomolecular engineering, is in charge of the group’s operations. He said the first technical challenge was perfecting the production process. The original group, which included Christine Robichaud, a graduate student in civil and environmental engineering, and undergraduates Guyton Durnin and Lizzi Clark, overcame early technical hurdles using a pilot reactor in Zygourakis’ lab. The reactor makes the small batches that Perez burns in his mower.

RUBI now boasts more than a dozen faculty, staff and student members, and it’s gotten financial and faculty support from the Shell Center for Sustainability, both Alvarez’s and Zygourakis’ departments, as well as the Energy and Environmental Systems Institute. Yarrison said RUBI is putting the finishing touches on a 70-gallon reactor in its headquarters on the loading dock of Sid Richardson College. By the fall, Yarrison said the group hopes to produce 50 to 100 gallons of biodiesel per week.

RUBI is currently using a blend of 20 percent biodiesel and 80 percent petroleum diesel to power Rice mowers. Yarrison said the group hopes to start using pure biodiesel by year’s end. To ensure that the biodiesel produced is of fuel-grade quality, RUBI is acquiring the final pieces of lab equipment it will need to certify each batch of fuel under nationally accepted American Society for Testing and Materials standards. Certifying the fuel will provide assurance that RUBI’s fuel is safe for use in all diesel engines.

“That’s better quality control than what you’d get on the diesel you buy at the pump,” Yarrison said.

About Jade Boyd

Jade Boyd is science editor and associate director of news and media relations in Rice University's Office of Public Affairs.